Waterbeds have come into widespread use during the past decade. A typical waterbed consists of a water filled bladder supported by a rigid frame. Although early users were primarily younger people attracted by the novelty and low cost of waterbeds, a wider range of consumers have been attracted to waterbeds in recent years for a number of reasons. Perhaps the most important reason is the fact that waterbed mattresses provide uniform support to the sleeper, eliminating "pressure points" on which most of the weight of the body rests when reclining on conventional nonfluid sleeping surfaces. However, there remain a number of drawbacks to be overcome before waterbeds will be readily accepted in the conventional bedding market.
A universal problem in waterbeds to date has been the annoying wave motion set up in the water whenever a person changes position on the waterbed mattress. Generally, a series of transverse waves are set up which are reflected by the lateral walls of the waterbed. Because of this reflecting action, the waves usually continue for several seconds before dampening out. In order to eliminate this problem, it is desirable to make this dampening period as short as possible without impairing other positive features of the waterbed.
Prior inventors have sought to increase the dampening action in waterbeds by a number of different internal baffle arrangements.
Carson, et. al., U.S. Pat. No. 3,736,604, disclose a waterbed mattress with flexible internal baffles welded to the top inside surface of the mattress which also provides that weights may be added to the lower edge of the baffles to increase the dampening action.
Labianco, U.S. Pat. No. 3,840,921 discloses a waterbed mattress with two flexible baffles attached to the upper and lower inner surface of the mattress.
Fogel, U.S. Pat. No. 4,145,780 disclose a waterbed mattress with baffles formed by heat welding flexible plastic sheets to the bottom inside surface of the mattress and attaching the upper edge of each sheet to a flotation rod.
It must be noted that in each of the baffle systems disclosed in the prior art, it was necessary in some way to attach each baffle to at least one inner surface of the waterbed mattress. The costs associated with attaching the baffles to the mattress are likely to be substantial because of the additional number of production steps required. Another problem with baffle systems can be appreciated from the fact that the Carson arrangement provided for weights to be added to the baffles to increase the dampening effect. The problem arises from the fact that if the baffles are too flexible or of insufficient mass, they will be ineffective as a dampening means. However, if the baffles are sufficiently massive and stiff to provide good dampening, they may interfere with the performance of the waterbed mattress. Stiff or massive baffles introduce uncomfortable ridges near the sleeping surface and also make it difficult to collapse the waterbed mattress for storage or shipment.
In summary, means for dampening wave action in waterbeds are disclosed in the art and in prior patents. However, all of these dampening means greatly increase fabrication costs and involve trade offs with other desirable features of the waterbed mattress.